Self-Templated Formation of Uniform F-CuO Hollow Octahedra for Lithium Ion Batteries

The formation of unique hollow structures with designable structural features has been achieved via tunable structure-evolution reaction. Uniform hollow CuO octahedral doped with FeOOH (denoted as F-CuO hollow octahedra) were used. 50 mg CuO octahedral sample was dispersed in 40 mL 99.9% ethanol and then 50 mg of FeCl₂ was added into the solution. The mixture was sealed in a 45 mL Teflon-lined autoclave and maintained at 170°C for 60 min. After the reaction, the final products were cooled down to room temperature and the precipitates were collected followed by washing with deionized water and ethanol. A piece of copper foil with a typical dimension of 10 mm × 10 mm was heated on a hot plate in air for 2 d. The morphologies of the samples were investigated by using a FESEM. It is found that a delicate control of reaction agents has an important influence on the composition and morphology of the product. When utilized as anodes in LIBs, the amorphous FeOOH doped hollow CuO octahedra demonstrate very good lithium storage properties, delivering a large reversible apacity as high as 624 mAh g^-1 at 1 A g^-1, even after 300 cycles. It is worth mentioning that this procedure can be extended to fabricate other nonspherical hollow structured CuO-based metal oxides.